As far as we know, there has been no logical examination of the conceptual plausibility of altruism as a personality construct. Inferences from empirical studies, most notably those of Samuel and Pearl Oliner (1988) and of Kristin Renwick Monroe (1996), strongly support the existence of altruistic acts and underlying altruistic personalities. Yet, despite abundant and persuasive evidence that altruists exist, their personalities remain puzzling. They appear to involve inconsistent, or paradoxical, elements. This issue is of critical importance: the incoherency of the altruistic personality would undermine the possibility that there are persons for whom genuine concern for the good of others is an integral part of personality. In this essay we highlight and offer a resolution to the apparent paradox of the altruistic personality. We argue that the altruistic personality is a coherent construct after all.